As a scroll compressor capable of increasing the compression volume without increasing the outer diameter of scroll members, a scroll compressor has been proposed including shoulder sections at an end surface and a bottom surface of each spiral wrap of a paired fixed scroll member and revolving scroll member, wherein three-dimensional compression is possible in a circumferential direction and a height direction of the spiral wrap by setting a spiral wrap height of the spiral wrap further outward than the shoulder sections greater than the spiral wrap height on the inward side. Since such a compressor is capable of performing compression not only in the circumferential direction of the spiral wraps but also in the wrap height direction, displacement is increased and the compression volume is increased compared with conventional scroll compressors (two-dimensional compression). Therefore, when compared with a compressor having the same volume, advantages such as size reduction and weight reduction are achieved.
In the above-described scroll compressor, stress due to a pressure difference ΔP acting upon both sides of the spiral wraps is applied to the bases of the shoulder sections provided on which the spiral wraps. Patent Document 1 describes a compressor provided with ribs, which are constructed by providing minute corners R at the bases of the shoulder sections, in order to reduce the stress concentration at the bases. Patent Document 2 describes a compressor that is provided with step-like surfaces with a minute height at a notch in a tip seal at the shoulder section to reduce gas leakage from the tip gap at the notch at the tip seal.
Patent Document 1:
Japanese Unexamined Patent Application, Publication No. 2002-5046 (paragraphs [0029] to [0030] and FIG. 4)
Patent Document 2:
Japanese Unexamined Patent Application, Publication No. 2006-342776 (paragraphs [0021] to [0024] and FIG. 1)